Laminated gripping dog



June 22, 1943.

c. M. MaccHEsNEY 2,322,651

LAMINATED GRIPPING DOG' Filed Oct. 31, 1940 2 Sheets-Sheet 1 June 22, 1943. C. M. MacCHEsNEY LAMINATED GRIPPING DOG 2 Sheets-Sheet. 2

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zdf@ 2d 24@ Q2/Q 2%' 20g 22e Patented June 22, 1943 LAMINATED' GRIPPING DOG ChesterM. MacCheSnemGhicago, Ill., assigner to Acme Steel Company', Chicago,` Ill., a/corpora-A tion ofv Illinois Application-October 31, 1940, Serial No. 363,675*

1 Claim.

This invention relates to improvements in gripping dogs,- and its'purpose isf to provide improved means'adapted for use on'strap lstretching andsealing devices, and on-other tools, for securely` holding a metal strapv or other binder in' fixed" position with respect to apart of the tool: It'has' been common practice to'provide tools` of this kind with pivoted gripping dogsadaptedY to holdV thestrap or binderV against aflangeorfbase plate seated on the boX-, pack-age or other object to bebound, and these dogs have heen'a-ctuated by gravity or by springsin order to forcethem into linitial engagement with the straporbincler.V In order tohold a at metal strap-properly, it isdesirable that the `gripping dogbe substantially coextensive in width with the strap, andthis hasbeenrtheusual-practice, bu-tfithasbeen-found that such a dog frequently fails. tof hold thelfstrap-securely throughout its Width-because -of Variations in the gauge of*` they metal stra-p between. its. edges.n Asi-a resultuof this uneven thickness, or asa-resultof bending` ofthe part on which the straprests, the strap..

may begripped only at one edge, for example,

and-f-When-l tension` is exertedupony theV strap; it may: slider beneath-the dog ortlheV excessive ten.- sionf created inone` side portionof the dog may cause-it to fail.

Theprincipal object of the present inventiony is-to.. overcome they foregongydiculty by pro..- viding an improved laminated gripping dog com prising` a plurality of relatively movable. parts. whichV may adjust. themselvesz to the. uneven thicknessor contour` of the strap or binder being held.` and. thereby.: exert a gripping action.

throughoutr the width. of. the. dog. Another fob.- ject is` to provide atpivoted` gripping dog. made; up; ofJ, a1 plurality. of laminations .arrangedV edge- Wise tolthesurface to be gripped and. provided,A preferably,` with means for normally movingi them-lindependently of each other toward the.,` article-tube gripped. A further object is Y.to providelatgripping device comprisinga base flange adaptedto support a strapand. having mounted f inl fixedv relation thereto a pivoted` ,laminated4 gripping. dogA provided with resilient means for forcing the laminations into engagement withV theJ strap and-` with means for simultaneously moving all of the laminationsl away from the stra-pwhen ite-isi desired to effect the releaseof: tlie stra-pl Another object isto simplify and. cheapen-fthe/ costi of construction 'of the device by providing a-gripping dog made up of a-series ofisimplerflat stampings,v thus saving the cost.Y ofe'accuratelyl machining the` member. Otherf objects relate to various features of constructionL4 and arrangement which will appear more fully hereinafter.

The nature ofthe invention willfbe understood from the followingspecification, taken witlrthe'4 yaccompanying drawings, in which two embodi- Fig. 3 shows anend elevation of the apparatus .I illustrated in Figs. l and 2, looking towardftheleft, as viewed in Fig. 2;

Fig. 4 shows a perspective viewof the spring by whichtheindividual laminationsrof thef-struc'- ture shown in Figs. l and 2 are forcedinto fnor-4 gripping dog shown in Figs. l, 2 and. 3 may be' moved simultaneously out of engagement with= the strap against the action of the sprngshown.

in Fig.` 4;

Fig. 7 is apartial topplan View, similar to that; of Fig. l, showing a modiediforrn oi the invention;

Fig. 8 shows a side elevation of the 'apparatusv illustrated in. Fig. .7 and;

Fig. 9 is a. horizontal` detail sec-tion taken' on` the line 9 9 of Fig. 8:

In Figs. 1 to` 6, inclusive,the invention is il-- lustrated as vbeing applied-to astrap stretching; or sealing'tool or otherfdevice embodying a frame I6 adapted to rest upon the box, package or other object to bebound and having a forward'- ly extendingbaselange I0.a uponwhich one end` of the at metal strap ll is.adapted.` to. seat. This frame may preferably be provided'with-an arm HB1 extending parallel .to thestrap and provided at vits end with a; forwardly extending ila-ngey FG over which thev strapA il? extends in passing around the box or package.

grippingsdog l2 which is pivotally mounted upon'v apin l3secured` in the frame: lli, as shown' in` Fig. 3,' and.provided-atitszouter end wit-hangen.`

The flange It)c serves-as a'support for preventing thetilting.; of the tool during the operation of the meche Y ship when the laminations are assembled. The

gripping dog thus has, in effect, an inclined position between the pin I3 and the base ilange Illa so that, when the strap II is inserted between the dog and the flange, a pull upon the strap II, toward the right as viewed in Fig. 2, will tend to increase the grip of the dog upon the strap. These laminations may be formed quickly and cheaply by stamping them from sheet steel or the like.

' In order to cause the laminations of the gripping dog to move normally into engagement with the strap, there is provided a spring I4 comprising an upright portion Ilia which is secured by screws I5 to an arm II),d which extends outwardly from the frame Il parallel to the pin i3. This spring I4 is reversely bent so that it has an inverted U-shaped coniguration and the body portion MF- is reinforced and stiifened by a flat supporting plate I6 of rectangular form which is secured to the arm IDd on the outer side ,of the portion Illa of the spring. lThe opposite downwardly extending part of the spring is slotted in a vertical plane to providea plurality of parallel resilient ngers lh each of which is adapted to contact with the end face I2c of one of the laminations I2EL of the gripping dog. These fingers Illb are adapted to rotate the laminations I2a independently of each other about the pin I3 so that they are moved normally to the positions shown by full lines in Fig. 2 where their serrated gripping surfaces I2b engage the upper side of the strap II.

In order to move all of the laminations of the gripping dog in a clockwise direction against the compression of the spring Id for the purpose of vreleasing the strap Ii, there is provided an operating lever I'I which is pivotally mounted on the'pin I3 adjacent the head Ilia. This operating lever has the form shown particularly in Fig. 6 where it is illustrated as comprising a vertical body portion I'Ia provided with an aperture adapted to be closely tted by the pin I3. From the upper end of this body portion there extends l an operating handle portion I'lb which is adapted to be engaged by the fingers of the operator for the 4purpose of moving the lever about its pivot. From the lower part of the body portion beneath the handle, an arm I'Ic extends inwardlyto contact with the faces I2d of the laminations of the gripping dog, as shown particularly in Figs. 2 and 3. By pressing down on the handle portion II1D of the operating lever, the arm I'Ic .will be caused to rotate all of the laminations of the gripping dog about the pin I3, thus pressing the ngers Mb of the spring toward the left, as shown by dotted lines in Fig. 2 where the gripping surfaces of the laminations are shown by dotted lines as being vout of contact with the strap. When the gripping dog laminations are thus elevated, the strap may be inserted or released and then, upon releasing the handle Il", the spring I4 will automatically return the laminations of the gripping dog to their gripping positions and the motion of the gripping dog will at the same time return the lever I1 to its normal position, shown in Fig. 2. The rotation of the lever I1 in a counterclockwise direction is limited by a pin I8 projecting from the frame which is adapted to contact with the free end of the arm I'Ic formed on the lever if an excessive movement of the lever occurs. The lever is thus retained at all times in a position where it may be conveniently engaged by the fingers of the operator. The resilient iingers Iflb act independently of each other to move the laminations of the gripping dog into engagement with the strap and thus the strap is gripped throughout its width regardless of variations and irregularities in its contour or thickness.

The form of the invention illustrated in Figs. 7, 8 and 9 differs primarily from the form described above in the character of the means which are provided for moving the laminations of the gripping dog normally into engagement with the strap. In this form, a frame 20 is provided with a forwardly extending base flange 2te upon which the strap 2i is adapted to seat, and this strap is held in engagement with the flange 28a by a' gripping dog 22 made up oi a plurality of parallel laminations 22a of identical conguration which are pivotally mounted upon a pin 23 secured in iixed position in the frame 26. Each lamination 22a is provided with a serrated gripping surface 22b which is located at one side of a vertical plane containing the axis of the pin 23 so that a pull upon the strap toward the right, as viewed in Fig, 8, will cause the laminations to increase their grip upon the strap whileia pull upon the strap in the opposite direction will tend to release the strap from the gripping dog. Y. I

The laminations of the gripping dog 22 are moved normally into engagement with the upper side of the strap 2| by a spring-pressed plunger 24 which is mounted to reciprocate in the guide-V way 25a of a block 25 secured to the side of the frame 2G by screws 2S. The guideway 25a is closed at its inner margin by the frame 20 and at its outer side by a plate 21, and within the chamber thus formed there is mounted a coil spring 28 which bears at one end against the end wall of the guideway while the other end thereof is seated in a circular recess 25e formed in the plunger 2A. This plunger is provided with upper and lower longitudinally extending flanges 24h.

laminations to be forced toward a position wherev they engage the strap 2l and the rubber block 29 will permit such relative angular adjustment oi the laminations 22a as may be necessary tov cause the gripping surfaces of all of the laminations to engage the strap regardless of the thick.

ness and surface configuration of the strap at different points throughout its width.

The laminations 222L of the gripping dog 22 are adapted to be moved simultaneously out of engagement with the strap 2I by means of an operating lever 30 which is identical in lform with theoperating lever I'Ipreviously described, having a body portion 33a pivoted on the pin 23 and provided with a, handle portion 30h adapted to be engaged by the fingers of the operator. This body portion 3l]a carries an inwardly extending arm 30 which is adapted to contact the upright faces 22d of the laminations, when the lever is moved angularly in a clockwise direction, thereby moving'all of the laminations out of engagement with the strap. The reverse angular movement o! the laminations 22a u-nder the iniiuence of the spring 28 may be limited by a pin 3l mounted 1n the frame and adapted to contact the upper side of the arm 30, as in the form of the invention rst described.

Although certain forms of the invention have been shown and described by Way of illustration, it will be understood that it may be embodied in various other constructions without departing from the scope of the appended claim.

I claim:

The combination in a gripping device, of a frame carrying a base ange, a gripping dog pivotally mounted on said frame and comprising a plurality of relatively movable laminations each adapted to engage a strap seated on said flange, an arm extending outwardly from said frame, a spring of inverted U-shaped cross section having one side attached to said arm and having the other side slotted to form a plurality of separate resilient fingers each engaging one of said laminations, and a lever pivotally mounted on said frame and having a part adapted to engage all of said laminations for forcing all of said laminations away from said ange.

CHESTER M. MACCHESNEY. 

